The present invention relates to a speed setting device for setting the speed of a working machine and more particularly, for setting the speed in an excavator.
A diesel engine normally has a regulator for controlling, via a lever on the fuel injection pump, the amount of fuel supplied to the combustion chamber of the engine, to drive the engine at a predetermined speed. In an excavator, the engine usually is placed in the rear part of the hinged machine frame, and the above-mentioned speed control can be actuated manually and variably from the driver's seat by use of a hand-wheel, as well as by use of a pushbutton on the control lever, said hand-wheel and said push-button being adapted, via an electromechanical control system, to control the movement to the lever on the fuel injection pump.
During the excavating work, the engine should operate at a speed suitable for the type of work. Before or during excavation, the operator can set, for instance by use of the hand-wheel, an initial speed which, together with the speed control device, provides an operating speed suitable for the work. As soon as the operator actuates his controls to carry out excavation, the engine speed is increased automatically from resting speed to working speed. If required, the device permits manual stepwise increase/decrease of the engine speed during work and automatic return to resting speed when no work is carried out.